Patent US3897539A successfully refreshed from Google Patents.
US3897539A
Expired / Lapsed
US
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Tail gas nitrogen oxide abatement process
Assignee: Gas Technology Institute
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Filing: 1973-07-26
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Granted: 1975-07-29
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Expires: 1993-07-26
Abstract
Abstract A method and system for abating nitrogen oxide in tail gas from nitric acid production. The system includes a rotary wheel reactor which has a preheat zone to raise the temperature of the inlet tail gas stream to ignition temperature, and a reaction zone wherein the nitrogen oxides are reduce, and wherein heat of reaction is removed as it is generated for preheating said tail gas stream, and to also prevent heat buildup which would be damaging to the catalysts in the reactor and to ancillary material equipment.
Inventors
- 👤 Donald K Fleming
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:45
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
210 words
A METHOD FOR ABATING NITROGEN OXIDE IN A TAIL GAS STREAM WHICH INCLUDES THE STEPS OF DELIVERING A TAIL GAS WASTE STREAM CONTAINING NITROGEN OXIDE TO THE OBVERSE FACE OF A ROTATING REFRACTORY WHEEL, SAID REFRACTORY WHEEL HAVING COMMUNICATING PATHWAYS FROM THE OBVERSE FACE TO REVERSE FACE, AND DIVIDED INTO A PREHEAT ZONE FOR PREHEATING THE GAS STREAM AND A REACTION ZONE FOR TREATING THE GAS STREAM BY AN OXIDATION-REDUCTION REACTION, SAID GAS STREAM BEING PREHEATED AS SAID PREHEAT ZONE OF SAID WHEEL, COLLECTING SAID TAIL GAS STREAM AT THE REVERSE FACE TO THE ROTATING WHEEL AFTER MOVEMENT THROUGH SAID PREHEAT ZONE, SAID TAIL GAS BEING PREHEATED TO IGNITION TEMPERATURE, COMBINING SAID PREHEAT TAIL GAS STREAM WITH A STREAM OF REDUCING GAS, MOVING SAID COMBINED STREAM THROUGH THE REACTION ZONE OF THE WHEEL TO REDUCE THE NITROGEN OXIDE IN SAID TAIL GAS STREAM AT A REACTION TEMPERATURE WHICH UPPER LIMIT IS SUFFICIENTLY LOW TO SUBSTANTIALLY REDUCE THERMAL DAMAGE TO THE MATERIALS USED, THE HEAT OR REACTION DEVELOPED AT SAID REACTION ZONE MOVING WITH THE WHEEL TO THE PREHEAT ZONE TO AGAIN PREHEAT A DELIVERED TAIL GAS STREAM, AND COLLECTING AN EXHAUST GAS STREAM AT A REDUCED OUTLET TEMPERATURE AFTER MOVEMENT THROUGH SAID REACTION ZONE WHEREIN ABATEMENT OF NITROGEN OXIDE OCCURS.
Claim 2
Independent Claim
210 words
A METHOD FOR ABATING NITROGEN OXIDE IN A TAIL GAS STREAM WHICH INCLUDES THE STEPS OF DELIVERING A TAIL GAS WASTE STREAM CONTAINING NITROGEN OXIDE TO THE OBVERSE FACE OF A ROTATING REFRACTORY WHEEL, SAID REFRACTORY WHEEL HAVING COMMUNICATING PATHWAYS FROM THE OBVERSE FACE TO REVERSE FACE, AND DIVIDED INTO A PREHEAT ZONE FOR PREHEATING THE GAS STREAM AND A REACTION ZONE FOR TREATING THE GAS STREAM BY AN OXIDATION-REDUCTION REACTION, SAID GAS STREAM BEING PREHEATED AS SAID PREHEAT ZONE OF SAID WHEEL, COLLECTING SAID TAIL GAS STREAM AT THE REVERSE FACE TO THE ROTATING WHEEL AFTER MOVEMENT THROUGH SAID PREHEAT ZONE, SAID TAIL GAS BEING PREHEATED TO IGNITION TEMPERATURE, COMBINING SAID PREHEAT TAIL GAS STREAM WITH A STREAM OF REDUCING GAS, MOVING SAID COMBINED STREAM THROUGH THE REACTION ZONE OF THE WHEEL TO REDUCE THE NITROGEN OXIDE IN SAID TAIL GAS STREAM AT A REACTION TEMPERATURE WHICH UPPER LIMIT IS SUFFICIENTLY LOW TO SUBSTANTIALLY REDUCE THERMAL DAMAGE TO THE MATERIALS USED, THE HEAT OR REACTION DEVELOPED AT SAID REACTION ZONE MOVING WITH THE WHEEL TO THE PREHEAT ZONE TO AGAIN PREHEAT A DELIVERED TAIL GAS STREAM, AND COLLECTING AN EXHAUST GAS STREAM AT A REDUCED OUTLET TEMPERATURE AFTER MOVEMENT THROUGH SAID REACTION ZONE WHEREIN ABATEMENT OF NITROGEN OXIDE OCCURS.
Claim 3
Dependent Claim
76 words
A method includes the steps of claim 1 above wherein said various streams move in a path substantially normal to the faces of said wheel, said tail gas stream entering one face at an area of the preheat zone and leaving the opposite face following preheating, said tail gas re-entering said wheel at an area of the reaction zone and thereafter leaving the wheel after passing through the reaction zone in it as an exhaust gas.
Claim 4
Dependent Claim
22 words
A method which includes the steps of claim 2 above wherein a catalyst is distributed through the material of the refractory wheel.
Claim 5
Dependent Claim
71 words
A method which includes the steps of claim 3 above wherein said tail gas stream is delivered with an oxygen content from about 2 to about 4 percent by weight, wherein said tail gas is preheated from about 800*F to about 1000*F after passing through the preheat zone, and wherein said exhaust gas leaves the wheel after passing through said reaction zone at a reaction temperature of less than about 1200*F.
Claim 6
Dependent Claim
33 words
A method which includes the steps of claim 3 above wherein said refractory wheel is a unitary ceramic body having the catalyst distributed substantially uniformly therethrough, said catalyst being a platinum group metal.
Claim 7
Dependent Claim
19 words
A method which includes the steps of claim 5 above wherein said stream of reducing gas is natural gas.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-28 | 1979-01-27 | 1979-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-28 | 1983-01-27 | 1983-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-28 | 1987-01-27 | 1987-07-29 | $7700.00 | Window Closed / Lapsed |